Friction modifiers for improved anti-shudder performance and high static friction in transmission fluids

ABSTRACT

A fluid composition of (a) a friction modifier derived from the reaction of a carboxylic acid or a reactive equivalent thereof with an aminoalcohol, the friction modifier containing at least two hydrocarbyl groups; and (b) a dispersant other than a species of (a), provides good friction properties to an automatic transmission.

This application claims priority from U.S. Provisional Applications60/395,374 (12 Jul. 2002) and 60/418,601 (15 Oct. 2002).

BACKGROUND OF THE INVENTION

The present invention relates to the field of additives for fluids suchas automatic transmission fluids, traction fluids, fluids forcontinuously variable transmission fluids (CVTs), dual clutch automatictransmission fluids, farm tractor fluids, and engine lubricants.

In the automatic transmission marketplace, where there is rapidengineering change driven by the desire to reduce weight and increasetransmission capacity, there is a desire for automatic transmissionfluids that exhibit a high static coefficient of friction for improvedclutch holding capacity. At the same time, there is a desire to improvethe retention of positive slope characteristics in the mu/v (coefficientof friction vs. sliding speed) curve. There are newer tests in themarketplace which are used to define these characteristics. The statictorque can be measured in tests such as the Toyota SAE#2 friction testprocedure and the retention of positive slope can be measured byprocedures like the JASO LVFA (Japan Automotive Standards Organization,Low Velocity Friction Apparatus) in which the slope of the mu/v curve isperiodically measured during oxidative and mechanical aging.

There are patents, for example, U.S. Pat. No. 5,750,476, where a type offriction modifier technology used to achieve this performance isdescribed. The combined requirements of high static coefficient offriction and durable positive slope are often incompatible withtraditional ATF friction modifier technology which is extremely welldescribed in the patent literature. Many of the commonly used frictionmodifiers result in a low static coefficient of friction and are notdurable enough on positive slope to be of sufficient use. Additionalpatent literature describing technology for retaining positive mu/v oranti-shudder characteristics include U.S. Pat. No. 5,858,929. These mayemploy metal detergents and combinations of friction modifiers.

U.S. Pat. No. 4,886,612 discloses a lubricating oil comprising at leastone of various products, which can be various imidazolines or anoxazoline of the structure

where R₂ and R₃ each represent CH₂OCOR₁, CH₂OH or H.

The present invention, therefore, solves the problem of developing newfriction modifiers to obtain high static coefficients of friction andmaintaining a durable positive slope during oxidative and mechanicalstressing of the friction system, particularly in an automatictransmission by the use of a friction modifier prepared by thecondensation a carboxylic acid (or a reactive equivalent thereof) withan amino alcohol; for example, the condensation of two moles ofisostearic acid with one mole of tris-hydroxymethylaminomethane (THAM).

SUMMARY OF THE INVENTION

The present invention provides a composition suitable for use in fluidssuch as transmission fluids, including automatic, continuously variable,dual clutch, and manual transmission fluids, as well as farm tractorfluids, engine lubricants, as well a gears and bearings, comprising thefollowing components:

A fluid composition, comprising:

(a) a friction modifier derived from the reaction of a carboxylic acidor a reactive equivalent thereof with an aminoalcohol, wherein thefriction modifier contains at least two hydrocarbyl groups, eachcontaining at least 6 carbon atoms; (Examples include the reactionproduct of isostearic acid or an alkyl succinic anhydride withtris-hydroxymethylaminomethane); and

(b) a dispersant other than a species of (a).

The present invention further provides a method for lubricating amechanical device such as transmission, tractor, engine, gearbox, orbearing, comprising supplying to said device the above composition; orsupplying a composition comprising the above-described frictionmodifier.

DETAILED DESCRIPTION OF THE INVENTION

Various preferred features and embodiments will be described below byway of non-limiting illustration.

Component (a) is a friction modifier with at least two substituenthydrocarbyl groups, for example, alkyl groups. Specific examples of thistype of component include the following condensation products:Isostearic acid/Trishydroxymethylamino methane (“THAM”)(2:1 mole ratio);Isostearic acid/2-Amino-2-ethyl-1,3-propanediol (2:1 mole ratio);Octadecyl succinic anhydride/ethanol amine/isostearic acid (1:1:1 moleratio); and any of the foregoing materials combined with propylene oxide(in, e.g., a 1:1 mole ratio).

These materials are derived by the condensation of an acid (1) with anaminoalcohol (2). The usual intention is to produce molecules whichcontain at least two hydrocarbyl groups attached to one central polargroup. In order to assure a reasonable degree of oil solubility for theproduct, the two hydrocarbyl groups should, together, contain a total ofat least 8 carbon atoms, preferably at least 12 or 16 carbon atoms. Eachsuch hydrocarbyl groups is typically a long chain alkyl groupscontaining, individually, at least 6 or 8 carbon atoms, such as 10 to30, or 12 to 24, or 14 to 20, or 16 to 18 carbon atoms. In certainembodiments one or two of the components of the condensation productcontain branched chains.

In each type of condensation product, the organo carboxylic acids orequivalents (e.g., anhydrides, acid halides, esters) (1) may be as shownin the specific examples, or be a similar carboxylic acid derived fromfatty acids from natural plant and animal oils or syntheticallyproduced. They are, generally, in the 8 to 30 carbon atom range and aresubstantially linear in character. Alternatively, they may contain 10 to24 carbon atoms, or 12 to 22 or 16 to 20 carbon atoms. Examples arestearic acid, palmitic acid, oleic acid, tall oil acids, acids derivedfrom the oxidation of hydrocarbons, substituted succinic acids,ether-acids derived from the addition of acrylates or methacrylates toalcohols, and the like. (The reaction products of the ether-acids willcontain the requisite hydrocarbyl groups provided that the groupsexhibit substantially hydrocarbon character despite the presence of theether functionality, as further described in the definition of“hydrocarbyl,” below.) Mixtures of acids can also be used, e.g.,isostearic acid and octadecyl succinic acid or -anhydride, such mixturesbeing useful when reacted with an aminoalcohol such as ethanolamine,described below.

The amine containing material (2) is an aminoalcohol, that is, amolecule containing both amine functionality and alcohol functionality.The amine functionality is preferably in the form of a nitrogen atomcontaining at least one replaceable hydrogen, that is, a primary orsecondary amine. Examples of amino alcohols aretris-hydroxymethylaminomethane, 2-amino-2-ethyl-1,3-propanediol, andethanol amine. Other amino alcohols are also of use in thiscondensation, including 3-amino-1-propanol, 2-amino-1-propanol,1-amino-2-propanol, 2-amino-2-methyl-1-propanol, 4-amino-1-butanol,5-amino-1-pentanol, 2-amino-1-pentanol, 2-amino-1,2-propanediol,2-amino-1,3-propanediol, 2-amino-2-methyl-1,3-propanediol,N-(2-hydroxyethyl)ethylenediamine,N,N-bis(2-hydroxyethyl)ethylenediamine, 1,3-diamino-2-hydroxypropane,N-N′-bis-(2-hydroxyethyl)ethylenediamine, and1-aminopropyl-3-diisopropanol amine.

The two hydrocarbyl groups present in component (a) generally originatefrom the hydrocarbyl portion of the acid reactant. In that case it isgenerally desirable that 2 moles of acid be reacted with 1 mole of theaminoalcohol, each of the two moles thereby providing one long chainhydrocarbyl group. This ratio may generally vary from 1.2:1 to 3:1, or1.6:1 to 2.5:1, or 1.9:1 to 2.1:1. It is recognized that in any reactionproduct there may be a mixture of products, and reacting in any of theabove ratios may lead to some 1:1 adduct, 2:1 adduct, 3:1 adduct, and soon, in statistical or other ratios depending in part on the relativeamounts of the starting materials. The fact that the product may includea portion of the 1:1 adduct does not remove such a product from thescope of the present invention, provided that at least a portion of theproduct contains the required two hydrocarbyl groups. Of course, if twodifferent species of acid are used, the ratios can be about 1:1:1, andso on; provided that the ratio moles of all such acids to the moles ofall the aminoalcohols will normally be about 2:1. Alternatively, if theaminoalcohol itself is the source of one long chain hydrocarbyl group,then a ratio of about 1:1 may be appropriate to provide the twohydrocarbyl groups per molecule. Such variations will be apparent to theperson skilled in the art.

The amount of component (a) in the compositions of the present inventionis generally 0.2 to 5.0 percent by weight of the finished fluidformulation. Preferably the amount of component (a) is 0.5 to 4 percentof the finished fluid formulation. More preferably the amount ofcomponent (a) is 1.0 to 2.5 percent of the finished fluid formulation.

Component (b) is a dispersant. It is described as “other than a speciesof (a),” in the event that some of the friction modifiers of (a) mayexhibit some dispersant characteristics. Examples of “carboxylicdispersants” are described in many U.S. patents including the following:U.S. Pat. Nos. 3,219,666, 3,316,177, 3,340,281, 3,351,552, 3,381,022,3,433,744, 3,444,170, 3,467,668, 3,501,405, 3,542,680, 3,576,743,3,632,511, 4,234,435, and Re 26,433.

Succinimide dispersants, a species of carboxylic dispersants, areprepared by the reaction of a hydrocarbyl-substituted succinic anhydride(or reactive equivalent thereof, such as an acid, acid halide, or ester)with an amine, as described above. The hydrocarbyl substituent groupgenerally contains an average of at least 8, or 20, or 30, or 35 up to350, or to 200, or to 100 carbon atoms. In one embodiment, thehydrocarbyl group is derived from a polyalkene. Such a polyalkene can becharacterized by an {overscore (M)}_(n) (number average molecularweight) of at least 500. Generally, the polyalkene is characterized byan {overscore (M)}_(n) of 500, or 700, or 800, or 900 up to 5000, or to2500, or to 2000, or to 1500. In another embodiment {overscore (M)}_(n)varies from 500, or 700, or 800, to 1200 or 1300. In one embodiment thepolydispersity {overscore (M)}_(w)/{overscore (M)}_(n)) is at least 1.5.

The polyalkenes include homopolymers and inter-polymers of polymerizableolefin monomers of 2 to 16 or to 6, or to 4 carbon atoms. The olefinsmay be monoolefins such as ethylene, propylene, 1-butene, isobutene, and1-octene; or a polyolefinic monomer, such as diolefinic monomer, such1,3-butadiene and isoprene. In one embodiment, the inter-polymer is ahomo-polymer. An example of a polymer is a polybutene. In one instanceabout 50% of the polybutene is derived from isobutylene. The polyalkenescan be prepared by conventional procedures.

In one embodiment, the succinic acylating agents are prepared byreacting a polyalkene with an excess of maleic anhydride to providesubstituted succinic acylating agents wherein the number of succinicgroups for each equivalent weight of substituent group is at least 1.3,e.g., 1.5, or 1.7, or 1.8. The maximum number of succinic groups persubstituent group generally will not exceed 4.5, or 2.5, or 2.1, or 2.0.The preparation and use of substituted succinic acylating agents whereinthe substituent is derived from such polyolefins are described in U.S.Pat. No. 4,234,435.

The substituted succinic acylating agent can be reacted with an amine,including those amines described above and heavy amine products known asamine still bottoms. The amount of amine reacted with the acylatingagent is typically an amount to provide a mole ratio of CO:N of 1:2 to1:0.75,. If the amine is a primary amine, complete condensation to theimide can occur. Varying amounts of amide product, such as the amidicacid, may also be present. If the reaction is, rather, with an alcohol,the resulting dispersant will be an ester dispersant. If both amine andalcohol functionality are present, whether in separate molecules or inthe same molecule (as in the above-described condensed amines), mixturesof amide, ester, and possibly imide functionality can be present. Theseare the so-called ester-amide dispersants.

“Amine dispersants” are reaction products of relatively high molecularweight aliphatic or alicyclic halides and amines, preferablypolyalkylene polyamines. Examples thereof are described in the followingU.S. Pat. Nos. 3,275,554, 3,438,757, 3,454,555, and 3,565,804.

“Mannich dispersants” are the reaction products of alkyl phenols inwhich the alkyl group contains at least 30 carbon atoms with aldehydes(especially formaldehyde) and amines (especially polyalkylenepolyamines). The materials described in the following U.S. patents areillustrative: U.S. Pat. Nos. 3,036,003, 3,236,770, 3,414,347, 3,448,047,3,461,172, 3,539,633, 3,586,629, 3,591,598, 3,634,515, 3,725,480,3,726,882, and 3,980,569.

Post-treated dispersants are also part of the present invention. Theyare generally obtained by reacting at carboxylic, amine or Mannichdispersants with reagents such as urea, thiourea, carbon disulfide,aldehydes, ketones, carboxylic acids, hydrocarbon-substituted succinicanhydrides, nitriles, epoxides, boron compounds (to give “borateddispersants”), or phosphorus compounds. Exemplary materials of this kindare described in the following U.S. Pat. Nos. 3,200,107, 3,282,955,3,367,943, 3,513,093, 3,639,242, 3,649,659, 3,442,808, 3,455,832,3,579,450, 3,600,372, 3,702,757, and 3,708,422.

Also included are dispersants that have been treated with boric acid,phosphorus acids or anhydrides, and 2,5-dimercaptothiadiazole (DMTD).Mixtures of dispersants can also be used.

The amount of component (b) in the compositions of the present inventionare generally 1.0 to 4.0%. Preferably the amount of component (b) is 2.0to 3.0%. More preferably the amount of component (b) is 2.2% to 2.8% ofthe final blended fluid formulation.

Other components which are conventionally employed in a transmissionfluid, in particular, and automatic transmission fluid (ATF) aretypically also present.

Among such components are an oil of lubricating viscosity. Such oilsinclude natural and synthetic lubricating oils and mixtures thereof. Ina fully formulated lubricant, the oil of lubricating viscosity isgenerally present in a major amount (i.e. an amount greater than 50percent by weight). Typically, the oil of lubricating viscosity ispresent in an amount of 75 to 95 percent by weight, and often greaterthan 80 percent by weight of the composition.

Natural oils useful in making the inventive lubricants and functionalfluids include animal oils and vegetable oils as well as minerallubricating oils such as liquid petroleum oils and solvent-treated oracid-treated mineral lubricating oils of the paraffinic, naphthenic ormixed paraffinic/-naphthenic types which may be further refined byhydrocracking and hydrofinishing processes.

Synthetic lubricating oils include hydrocarbon oils and halo-substitutedhydrocarbon oils such as polymerized and interpolymerized olefins, alsoknown as polyalphaolefins; polyphenyls; alkylated diphenyl ethers;alkyl- or dialkylbenzenes; and alkylated diphenyl sulfides; and thederivatives, analogs and homologues thereof. Also included are alkyleneoxide polymers and inter-polymers and derivatives thereof, in which theterminal hydroxyl groups may have been modified by esterification oretherification. Also included are esters of dicarboxylic acids with avariety of alcohols, or esters made from C5 to C12 monocarboxylic acidsand polyols or polyol ethers. Other synthetic oils include silicon-basedoils, liquid esters of phosphorus-containing acids, and polymerictetrahydrofurans.

Unrefined, refined and rerefined oils, either natural or synthetic, canbe used in the lubricants of the present invention. Unrefined oils arethose obtained directly from a natural or synthetic source withoutfurther purification treatment. Refined oils have been further treatedin one or more purification steps to improve one or more properties.They can, for example, be hydrogenated, resulting in oils of improvedstability against oxidation.

In one embodiment, the oil of lubricating viscosity a Group II or agroup III oil, or a synthetic oil, or mixtures thereof. Group II andGroup III oils are classifications established by the API Base OilInterchangeability Guidelines. Both Group II and Group III oils contain<0.03 percent sulfur and >99 percent saturates. Group II oils have aviscosity index of 80 to 120, and Group III oils have a viscosityindex >120. Polyalphaolefins are categorized as Group IV. The oil canalso be an oil derived from a Fischer-Tropsch synthesis.

In a preferred embodiment, at least 50% by weight of the oil oflubricating viscosity is a polyalphaolefin (PAO). Typically, thepolyalphaolefins are derived from monomers having from 4 to 30, or from4 to 20, or from 6 to 16 carbon atoms. Examples of useful PAOs includethose derived from 1-decene. These PAOs may have a viscosity of 1.5 to150 mm²/s (cSt) at 100° C. PAOs are typically hydrogenated materials.

The oils of the present invention can encompass oils of a singleviscosity range or a mixture of high viscosity and low viscosity rangeoils. In a preferred embodiment, the oil exhibits a 100° C. kinematicviscosity of 1 or 2 to 8 or 10 mm²/sec (cSt). The overall lubricantcomposition is preferably formulated using oil and other components suchthat the viscosity at 100° C. is 1 or 1.5 to 10 or 15 or 20 mm²/sec andthe Brookfield viscosity (ASTM-D-2983) at −40° C. is less than 20 or 15Pa-s (20,000 cP or 15,000 cP), preferably less than 10 Pa-s, even 5 orless.

The composition used in the present invention can also include a varietyof additional components. One component frequently used is a viscositymodifier. Viscosity modifiers (VM) and dispersant viscosity modifiers(DVM) are well known. Examples of VMs and DVMs are polymethacrylates,polyacrylates, polyolefins, styrene-maleic ester copolymers, and similarpolymeric substances including homopolymers, copolymers and graftcopolymers.

Examples of commercially available VMs, DVMs and their chemical typesinclude the following: polyisobutylenes (such as Indopol™ from BP Amocoor Parapol™ from ExxonMobil); Olefin copolymers (such as Lubrizol™ 7060,7065, and 7067 from Lubrizol and Trilene™ CP-40 and CP-60 fromUniroyal); hydrogenated styrene-diene copolymers (such as Shellvis™ 40and 50, from Shell and LZ® 7341, 7351, and 7441 from Lubrizol);Styrene/maleate copolymers, which are dispersant copolymers (such as LZ®3702, 3715, and 3703 from Lubrizol); polymethacrylates, some of whichhave dispersant properties (such as those in the Acryloid™ andViscoplex™ series from RohMax, the TLA™ series from Texaco, and LZ 7702™and LZ 7720™ from Lubrizol); olefin-graft-polymethacrylate polymers(such as Viscoplex™ 2-500 and 2-600 from Rohm GmbH); and hydrogenatedpolyisoprene star polymers (such as Shellvis™ 200 and 260, from Shell).Recent summaries of viscosity modifiers can be found in U.S. Pat. Nos.5,157,088, 5,256,752 and 5,395,539. The VMs and/or DVMs are incorporatedinto the fully-formulated compositions at a level of up to 15% byweight. Preferred amounts are 1 to 12% or 3 to 10%.

Another component that may be used in the composition used in thepresent invention is a supplemental friction modifier. Frictionmodifiers are well known to those skilled in the art. A useful list offriction modifiers is included in U.S. Pat. No. 4,792,410. U.S. Pat. No.5,110,488 discloses metal salts of fatty acids and especially zincsalts, useful as friction modifiers. A list of friction modifiersincludes:

(i) fatty phosphites

(ii) fatty acid amides

(iii) fatty epoxides

(iv) borated fatty epoxides

(v) fatty amines

(vi) glycerol esters

(vii) borated glycerol esters

(viii) alkoxylated fatty amines

(ix) borated alkoxylated fatty amines

(x) metal salts of fatty acids

(xi) sulfurized olefins

(xii) fatty imidazolines

(xiii) condensation products of carboxylic acids andpolyalkylene-polyamines

(xiv) metal salts of alkyl salicylates

(xv) amine salts of alkylphosphoric acids and mixtures thereof.

Representatives of each of these types of friction modifiers are knownand are commercially available. For instance, (i) fatty phosphites aregenerally of the formula (RO)₂PHO. The preferred dialkyl phosphite, asshown in the preceding formula, is typically present with a minor amountof monoalkyl phosphite of the formula (RO)(HO)PHO. In these structures,the term “R” is conventionally referred to as an alkyl group. It is, ofcourse, possible that the alkyl is actually alkenyl and thus the terms“alkyl” and “alkylated,” as used herein, will embrace other thansaturated alkyl groups within the phosphite. The phosphite should havesufficient hydrocarbyl groups to render the phosphite substantiallyoleophilic. Preferably the hydrocarbyl groups are substantiallyunbranched. Many suitable phosphites are available commercially and maybe synthesized as described in U.S. Pat. No. 4,752,416. It is preferredthat the phosphite contain 8 to 24 carbon atoms in each of R groups.Preferably, the fatty phosphite contains 12 to 22 carbon atoms in eachof the fatty radicals, most preferably 16 to 20 carbon atoms. In oneembodiment the fatty phosphite can be formed from oleyl groups, thushaving 18 carbon atoms in each fatty radical.

(iv) Borated fatty epoxides are known from Canadian Patent No.1,188,704. These oil-soluble boron-containing compositions are preparedby reacting, at a temperature from 80° C. to 250° C., boric acid orboron trioxide with at least one fatty epoxide having the formula

wherein each of R¹, R², R³ and R⁴ is hydrogen or an aliphatic radical,or any two thereof together with the epoxy carbon atom or atoms to whichthey are attached, form a cyclic radical. The fatty epoxide preferablycontains at least 8 carbon atoms.

The borated fatty epoxides can be characterized by the method for theirpreparation which involves the reaction of two materials. Reagent A canbe boron trioxide or any of the various forms of boric acid includingmetaboric acid (HBO₂), orthoboric acid (H₃BO₃) and tetraboric acid(H₂B₄O₇). Boric acid, and especially orthoboric acid, is preferred.Reagent B can be at least one fatty epoxide having the above formula. Inthe formula, each of the R groups is most often hydrogen or an aliphaticradical with at least one being a hydrocarbyl or aliphatic radicalcontaining at least 6 carbon atoms. The molar ratio of reagent A toreagent B is generally 1:0.25 to 1:4. Ratios of 1:1 to 1:3 arepreferred, with about 1:2 being an especially preferred ratio. Theborated fatty epoxides can be prepared by merely blending the tworeagents and heating them at temperature of 80° to 250° C., preferably100° to 200° C., for a period of time sufficient for reaction to takeplace. If desired, the reaction may be effected in the presence of asubstantially inert, normally liquid organic diluent. During thereaction, water is evolved and may be removed by distillation.

(iii) Non-borated fatty epoxides, corresponding to “Reagent B” above,are also useful as friction modifiers.

Borated amines are generally known from U.S. Pat. No. 4,622,158. Boratedamine friction modifiers (including (ix) borated alkoxylated fattyamines) are conveniently prepared by the reaction of a boron compounds,as described above, with the corresponding amines. The amine can be asimple fatty amine or hydroxy containing tertiary amines. The boratedamines can be prepared by adding the boron reactant, as described above,to an amine reactant and heating the resulting mixture at a 50° to 300°C., preferably 100° C. to 250° C. or 150° C. to 230° C., with stirring.The reaction is continued until by-product water ceases to evolve fromthe reaction mixture indicating completion of the reaction.

Among the amines useful in preparing the borated amines are commercialalkoxylated fatty amines known by the trademark “ETHOMEEN” and availablefrom Akzo Nobel. Representative examples of these ETHOMEEN™ materials isETHOMEEN™ C/12 (bis[2-hydroxyethyl]-coco-amine); ETHOMEEN™ C/20(polyoxyethylene[10]cocoamine); ETHOMEEN™ S/12(bis[2-hydroxyethyl]soyamine); ETHOMEEN™ T/12(bis[2-hydroxyethyl]-tallow-amine); ETHOMEEN™ T/15(polyoxyethylene-[5]tallowamine); ETHOMEEN™ 0/12(bis[2-hydroxyethyl]oleyl-amine); ETHOMEEN™ 18/12(bis[2-hydroxyethyl]octadecylamine); and ETHOMEEN™ 18/25(poly-oxyethyl-ene[15]octadecylamine). Fatty amines and ethoxylatedfatty amines are also described in U.S. Pat. No. 4,741,848.

The (viii) alkoxylated fatty amines, and (v) fatty amines themselves(such as oleylamine) are generally useful as friction modifiers in thisinvention. Such amines are commercially available.

Both borated and unborated fatty acid esters of glycerol can be used asfriction modifiers. The (vii) borated fatty acid esters of glycerol areprepared by borating a fatty acid ester of glycerol with boric acid withremoval of the water of reaction. Preferably, there is sufficient boronpresent such that each boron will react with from 1.5 to 2.5 hydroxylgroups present in the reaction mixture. The reaction may be carried outat a temperature in the range of 60° C. to 135° C., in the absence orpresence of any suitable organic solvent such as methanol, benzene,xylenes, toluene, or oil.

(vi) Fatty acid esters of glycerol themselves can be prepared by avariety of methods well known in the art. Many of these esters, such asglycerol monooleate and glycerol tallowate, are manufactured on acommercial scale. The esters useful are oil-soluble and are preferablyprepared from C8 to C22 fatty acids or mixtures thereof such as arefound in natural products and as are described in greater detail below.Fatty acid monoesters of glycerol are preferred, although, mixtures ofmono- and diesters may be used. For example, commercial glycerolmonooleate may contain a mixture of 45% to 55% by weight monoester and55% to 45% diester.

Fatty acids can be used in preparing the above glycerol esters; they canalso be used in preparing their (x) metal salts, (ii) amides, and (xii)imidazolines, any of which can also be used as friction modifiers.Preferred fatty acids are those containing 6 to 24 carbon atoms,preferably 8 to 18. The acids can be branched or straight-chain,saturated or unsaturated. Suitable acids include 2-ethylhexanoic,decanoic, oleic, stearic, isostearic, palmitic, myristic, palmitoleic,linoleic, lauric, and linolenic acids, and the acids from the naturalproducts tallow, palm oil, olive oil, peanut oil, corn oil, and Neat'sfoot oil. A particularly preferred acid is oleic acid. Preferred metalsalts include zinc and calcium salts. Examples are overbased calciumsalts and basic oleic acid-zinc salt complexes which can be representedby the general formula Zn₄Oleate₃O₁. Preferred amides are those preparedby condensation with ammonia or with primary or secondary amines such asdiethylamine and diethanolamine. Fatty imidazolines are the cycliccondensation product of an acid with a diamine or polyamine such as apolyethylenepolyamine. The imidazolines are generally represented by thestructure

where R is an alkyl group and R′ is hydrogen or a hydrocarbyl group or asubstituted hydrocarbyl group, including —(CH₂CH₂NH)n— groups. In apreferred embodiment the friction modifier is the condensation productof a C8 to C24 fatty acid with a polyalkylene polyamine, and inparticular, the product of isostearic acid with tetraethylenepentamine.The condensation products of carboxylic acids and polyalkyleneamines(xiii) may generally be imidazolines or amides.

Sulfurized olefins (xi) are well known commercial materials used asfriction modifiers. A particularly preferred sulfurized olefin is onewhich is prepared in accordance with the detailed teachings of U.S. Pat.Nos. 4,957,651 and 4,959,168. Described therein is a cosulfurizedmixture of 2 or more reactants selected from the group consisting of (1)at least one fatty acid ester of a poly-hydric alcohol, (2) at least onefatty acid, (3) at least one olefin, and (4) at least one fatty acidester of a monohydric alcohol.

Reactant (3), the olefin component, comprises at least one olefin. Thisolefin is preferably an aliphatic olefin, which usually will contain 4to 40 carbon atoms, preferably from 8 to 36 carbon atoms. Terminalolefins, or alpha-olefins, are preferred, especially those having from12 to 20 carbon atoms. Mixtures of these olefins are commerciallyavailable, and such mixtures are contemplated for use in this invention.

The cosulfurized mixture of two or more of the reactants, is prepared byreacting the mixture of appropriate reactants with a source of sulfur.The mixture to be sulfurized can contain 10 to 90 parts of Reactant (1),or 0.1 15 parts by weight of Reactant (2); or 10 to 90 parts, often 15to 60 parts, more often 25 to 35 parts by weight of Reactant (3), or 10to 90 parts by weight of reactant (4). The mixture, in the presentinvention, includes Reactant (3) and at least one other member of thegroup of reactants identified as reactants (1), (2) and (4). Thesulfurization reaction generally is effected at an elevated temperaturewith agitation and optionally in an inert atmosphere and in the presenceof an inert solvent. The sulfurizing agents useful in the process of thepresent invention include elemental sulfur, which is preferred, hydrogensulfide, sulfur halide plus sodium sulfide, and a mixture of hydrogensulfide and sulfur or sulfur dioxide. Typically often 0.5 to 3 moles ofsulfur are employed per mole of olefinic bonds.

Metal salts of alkyl salicylates (xiv) include calcium and other saltsof long chain (e.g. C12 to C16) alkyl-substituted salicylic acids.

Amine salts of alkylphosphoric acids (xv) include salts of oleyl andother long chain esters of phosphoric acid, with amines as describedbelow. Useful amines in this regard are tertiary-aliphatic primaryamines, sold under the tradename Primene™. The supplemental frictionmodifier can be used in addition to component (a). The amount of thesupplemental friction modifier is generally 0.1 to 1.5 percent by weightof the lubricating composition, preferably 0.2 to 1.0 or 0.25 to 0.75percent.

The compositions of the present invention can also include a detergent.Detergents as used herein are metal salts of organic acids. The organicacid portion of the detergent is a sulfonate, carboxylate, phenate,salicylate. The metal portion of the detergent is an alkali or alkalineearth metal. Preferred metals are sodium, calcium, potassium andmagnesium. Typically, the detergents are overbased, meaning that thereis a stoichiometric excess of metal over that needed to form the neutralmetal salt.

Preferred overbased organic salts are the sulfonate salts having asubstantially oleophilic character and which are formed from organicmaterials. Organic sulfonates are well known materials in the lubricantand detergent arts. The sulfonate compound should contain on average 10to 40 carbon atoms, preferably 12 to 36 carbon atoms and preferably 14to 32 carbon atoms on average. Similarly, the phenates, salicylates, andcarboxylates have a substantially oleophilic character.

While the present invention allows for the carbon atoms to be eitheraromatic or in paraffinic configuration, it is preferred that alkylatedaromatics be employed. While naphthalene based materials may beemployed, the aromatic of choice is the benzene moiety.

The most preferred composition is thus an overbased monosulfonatedalkylated benzene, and is preferably the monoalkylated benzene.Typically, alkyl benzene fractions are obtained from still bottomsources and are mono- or di-alkylated. It is believed, in the presentinvention, that the mono-alkylated aromatics are superior to thedialkylated aromatics in overall properties.

It is desired that a mixture of mono-alkylated aromatics (benzene) beutilized to obtain the mono-alkylated salt (benzene sulfonate) in thepresent invention. The mixtures wherein a substantial portion of thecomposition contains polymers of propylene as the source of the alkylgroups assist in the solubility of the salt. The use of mono-functional(e.g., mono-sulfonated) materials avoids crosslinking of the moleculeswith less precipitation of the salt from the lubricant.

It is preferred that the salt be “overbased.” By overbasing, it is meantthat a stoichiometric excess of the metal be present over that requiredto neutralize the anion of the salt. The excess metal from overbasinghas the effect of neutralizing acids which may build up in thelubricant. A second advantage is that the overbased salt increases thedynamic coefficient of friction. Typically, the excess metal will bepresent over that which is required to neutralize the anion at in theratio of up to 30:1, preferably 5:1 to 18:1 on an equivalent basis.

The amount of the overbased salt utilized in the composition istypically 0.025 to 3 weight percent on an oil free basis, preferably 0.1to 1.0 percent. The overbased salt is usually made up in about 50% oilwith a TBN range of 10-600 on an oil free basis. Borated and non-boratedoverbased detergents are described in U.S. Pat. Nos. 5,403,501 and4,792,410 which are herein incorporated by reference for disclosurepertinent hereto.

The compositions of the present invention can also include at least onephosphorus acid, phosphorus acid salt, phosphorus acid ester orderivative thereof including sulfur-containing analogs in the amount of0.002-1.0 weight percent. The phosphorus acids, salts, esters orderivatives thereof include phosphoric acid, phosphorous acid,phosphorus acid esters or salts thereof, phosphites,phosphorus-containing amides, phosphorus-containing carboxylic acids oresters, phosphorus-containing ethers, and mixtures thereof.

In one embodiment, the phosphorus acid, ester or derivative can be anorganic or inorganic phosphorus acid, phosphorus acid ester, phosphorusacid salt, or derivative thereof. The phosphorus acids include thephosphoric, phosphonic, phosphinic, and thiophosphoric acids includingdithiophosphoric acid as well as the monothiophosphoric, thiophosphinicand thiophosphonic acids. One group of phosphorus compounds arealkylphosphoric acid mono alkyl primary amine salts as represented bythe formula

where R¹, R², R³ are alkyl or hydrocarbyl groups or one of R¹ and R² canbe H. The materials can be a 1:1 mixture of dialkyl and monoalkylphosphoric acid esters. Compounds of this type are described in U.S.Pat. No. 5,354,484.

Eighty-five percent phosphoric acid is a preferred material for additionto the fully-formulated compositions and can be included at a level of0.01-0.3 weight percent based on the weight of the composition,preferably 0.03 to 0.1 percent.

Other materials can optionally be included in the compositions of thepresent invention, provided that they are not incompatible with theaforementioned required components or specifications. Such materialsinclude antioxidants (that is, oxidation inhibitors), including hinderedphenolic antioxidants, secondary aromatic amine antioxidants, sulfurizedphenolic antioxidants, oil-soluble copper compounds,phosphorus-containing antioxidants, organic sulfides, disulfides, andpolysulfides. Other optional components include seal swell compositions,such as isodecyl sulfolane or phthalate esters, which are designed tokeep seals pliable. Also permissible are pour point depressants, such asalkylnaphthalenes, polymethacrylates, vinyl acetate/fumarate or /maleatecopolymers, and styrene/maleate copolymers. These optional materials areknown to those skilled in the art, are generally commercially available,and are described in greater detail in published European PatentApplication 761,805. Also included can be corrosion inhibitors, dyes,fluidizing agents, odor masking agents, and antifoam agents.

The above components can be in the form of a fully-formulated lubricantor in the form of a concentrate within a smaller amount of lubricatingoil. If they are present in a concentrate, their concentrations willgenerally be directly proportional to their concentrations in the moredilute form in the final blend.

EXAMPLES

Examples 1-14 are prepared in the following base formulation: amount(%): 100 N Base oil 60.2 55 N-60 N Base oil 25.8 Dispersant (b) 2.4 DMTDtreated dispersant 0.6 Alkyl dimercaptothiadiazole 0.03Mono&dialkyldiphenyl amines (alkyl groups can 0.6 include butyl, heptyl,octyl, nonyl) 2-Propanol,1-(tert-dodecylthio)- 0.5 Alkyl sulfone sealswell agent 0.4 Borated C14 to C18 epoxide 0.2 Component (a) (as definedbelow) 2.5 or in another amount as illustrated below Polymethacrylatepour point depressant 0.2 Polymethacrylate viscosity modifier 4 Dialkylhydrogen phosphite antiwear agent 0.11 Oil diluent 0.26 85% Phosphoricacid 0.1 Red dye 0.025 Polydimethylsiloxane, 10% solution 0.03

Testing of the compositions described above is carried out as follows:The static friction is expressed in term of μT or the stabilized staticcoefficient the SAE#2 test procedure. The test procedure is described inthe Japanese mobile Standard, JASO M-348-95, “Test method for frictionproperty of Automatic transmission fluids”.

Testing gives the following results: Toyota JASO LVFA SAE #2 Screen Baseformulation + component (a) as Average Average Ex. shown below μT Slope× 10 1 “Good Reference” - a commercial 0.153 0.048 formulation 2 Base +0.5% Isostearic acid/polyamine 0.131 0.012 friction modifier * 3 Basewithout friction modifier 0.189 −0.112 (“FM”) * 4 Base + 0.5% ODSA/DETA(2:1) 0.186 0.011 (Reference FM) * 5 Base + 2.5% ODSA/DETA (2:1) 0.1690.033 (Reference FM) * 6 Base + 0.5% Dilauryl phosphite * 0.173 −0.096 7Base + 0.5% Ethomeen C-12 * 0.137 −0.120 8 Base + 0.5% Oleicacid/Diethanol- 0.152 0.003 amine (1:1)m * 9 Base + 0.5% commercialsynthetic 0.185 −0.043 ester friction modifier * 10 Base + 2.5%Octadecylsuccinic 0.139 0.043 anhydride/Duomeen T(1:1)m * 11 Base + 2.5%Isostearic Acid/Duomeen 0.103 0.105 T(1:1)m * 12 Base + 2.5% IsostearicAcid/ 0.156 0.041 THAM(2:1)m 13 Base + 0.5% Glycerol Monooleate * 0.174−0.004 14 Base + 0.5% Ethomeen T-12 * 0.138 —* -- a comparative example.ODSA = Octadecylsuccinic anhydride

It is preferred that μT is equivalent or better than the “GoodReference” and the Slope X10 is as high as possible compared to the“Good Reference” ATF. In some preferred examples, μT is at least 0.150and the average slope is positive, e.g., greater than 0.033 or at least0.040.

The results show that the friction modifier (a) in combination with thedispersant (b) provide a high level of static friction μT while theslope of the JASO LVFA screen test remains positive for 40 hours. Theseresults are equivalent to the Reference oil exhibiting these properties.

Example 15

A lubricant formulation is prepared by combining the followingcomponents (percentages are by weight):

0.30% product of isostearic acid and THAM (2:1 mole ratio)

0.375% dispersant from polybutene substituted succinic anhydride anddiethanolamine (including 33% diluent oil)

0.20% polybutene substituted succinic anhydride

1.0% dialkyl hydrogen phosphite

0.5% borate ester

1.15% zinc dialkyl dithiophosphates (including 11% diluent oil)

0.2% amine salt of alkyl phosphate

3.0% overbased calcium sulfonate detergent (including 52% diluent oil)

200 ppm antifoam agent

balance: base oil formulation (including viscosity modifier) andadditional diluent oil.

The formulation of Example 15 is subjected to the SAE #2 friction testand found to have a static coefficient of friction of 0.108-0.109. Thecoefficients of friction at 1200 r.p.m. (μ1200) and 0 r.p.m. (μ0) aremeasured, and the value of μ0/μ1200 determined to be 1.025. Theformulation thereby exhibits good friction performance for use as atractor hydraulic fluid.

Example 16

A lubricant formulation suitable for use as an engine oil lubricant isprepared by combining the following components (percentages by weight):

0.2% product of isostearic acid and THAM (2:1 mole ratio)

5.1% succinimide dispersant (including 55% diluent oil)

1.53% overbased calcium alkylbenzenesulfonate detergent(s), TBN 300-400(including 42% diluent oil)

0.20% hindered phenol ester antioxidant

0.70% amine antioxidant

0.98% zinc dialkyldithiophosphate (including 9% oil)

0.1% sulfurized olefin (including 5% oil)

90 ppm commercial antifoam product

balance: base oil formulation (including viscosity modifier) andadditional diluent oil.

Examples 17 and 18

The following formulations are prepared suitable for use as automatictransmission lubricants (amounts in parts by weight): Material Ex. 17Ex. 18 API Group 2 base oil 100 100 Methacrylate polymer pour pointdepressant 0.30 0.20 (35-40% oil) Methacrylate copolymer viscositymodifier, 5.0 5.0 nitrogen containing (with 26.5% oil) Succinimidedispersant(s) (40-43% oil) 4.0 4.2 Dimercaptothiadiazole-containingdispersant 0.50 1.00 (49% oil) Borated succinimide dispersant (33% oil)0.50 Product of isostearic acid and THAM (2:1 1.25 1.25 mole ratio)Borate ester friction modifier 0.20 0.20 Overbased Caalkylbenzenesulfonate 0.30 0.07 detergent, 300 TBN (50% oil) Caalkylbenzenesulfonate detergent, 10 TBN 0.84 (50% oil) Dibutyl hydrogenphosphite anti-wear agent 0.20 0.11 85% Aqueous phosphoric acid 0.030.10 Dimercaptothiadiazole oxidation inhibitor 0.03 0.04 Aromatic amineoxidation inhibitor 0.40 0.60 Sulfurized alcohol oxidation inhibitor0.50 0.50 Sulfolane seal swell agent 0.80 1.20 Commercial antifoamproduct(s) 0.03 0.034 Dye 0.025 0.025 Odorant 0.002 0.002 Additionaldiluent oil 0.45 0.53

The formulations of Examples 17 and 18 meet the requirements of theMerconV® low speed test for antishudder. The MerconV® low speed testdefines the acceptable antishudder requirements for automatictransmission fluids for Ford Motor Company vehicles. These formulationsshow that the friction modifier component is effective in formulationshaving very high (Ex. 17) to very low (Ex. 18) ash content ascontributed by calcium alkylbenzene sulfonate detergent(s).

As used herein, the term “hydrocarbyl substituent” or “hydrocarbylgroup” is used in its ordinary sense, which is well-known to thoseskilled in the art. Specifically, it refers to a group having a carbonatom directly attached to the remainder of the molecule and havingpredominantly hydrocarbon character. Examples of hydrocarbyl groupsinclude:

hydrocarbon substituents, that is, aliphatic (e.g., alkyl or alkenyl),alicyclic (e.g., cycloalkyl, cycloalkenyl) substituents, and aromatic-,aliphatic-, and alicyclic-substituted aromatic substituents, as well ascyclic substituents wherein the ring is completed through anotherportion of the molecule (e.g., two substituents together form a ring);

substituted hydrocarbon substituents, that is, substituents containingnon-hydrocarbon groups which, in the context of this invention, do notalter the predominantly hydrocarbon substituent (e.g., halo (especiallychloro and fluoro), hydroxy, alkoxy, mercapto, alkylmercapto, nitro,nitroso, and sulfoxy);

hetero substituents, that is, substituents which, while having apredominantly hydrocarbon character, in the context of this invention,contain other than carbon in a ring or chain otherwise composed ofcarbon atoms. Heteroatoms include sulfur, oxygen, nitrogen, andencompass substituents as pyridyl, furyl, thienyl and imidazolyl. Ingeneral, no more than two, preferably no more than one, non-hydrocarbonsubstituent will be present for every ten carbon atoms in thehydrocarbyl group; typically, there will be no non-hydrocarbonsubstituents in the hydrocarbyl group.

It is known that some of the materials described above may interact inthe final formulation, so that the components of the final formulationmay be different from those that are initially added. For instance,metal ions (of, e.g., a detergent) can migrate to other acidic sites ofother molecules. The products formed thereby, including the productsformed upon employing the composition of the present invention in itsintended use, may not susceptible of easy description. Nevertheless, allsuch modifications and reaction products are included within the scopeof the present invention; the present invention encompasses thecomposition prepared by admixing the components described above.

Each of the documents referred to above is incorporated herein byreference. Except in the Examples, or where otherwise explicitlyindicated, all numerical quantities in this description specifyingamounts of materials, reaction conditions, molecular weights, number ofcarbon atoms, and the like, are to be understood as modified by the word“about.” Unless otherwise indicated, each chemical or compositionreferred to herein should be interpreted as being a commercial gradematerial which may contain the isomers, by-products, derivatives, andother such materials which are normally understood to be present in thecommercial grade. However, the amount of each chemical component ispresented exclusive of any solvent or diluent oil which may becustomarily present in the commercial material, unless otherwiseindicated. It is to be understood that the upper and lower amount,range, and ratio limits set forth herein may be independently combined.As used herein, the expression “consisting essentially of” permits theinclusion of substances which do not materially affect the basic andnovel characteristics of the composition under consideration.

1. A fluid composition, comprising: (a) a friction modifier derived fromthe reaction of a carboxylic acid or a reactive equivalent thereof withan aminoalcohol, wherein the friction modifier contains at least twohydrocarbyl groups, each containing at least about 6 carbon atoms; and(b) a dispersant other than a species of (a).
 2. The composition ofclaim 1 wherein the aminoalcohol is trishydroxy-methylaminomethane. 3.The composition of claim 1 wherein the carboxylic acid and theaminoalcohol are reacted in a mole ratio of about 1.2:1 to 3:1.
 4. Thecomposition of claim 1 wherein the carboxylic acid is isostearic acid.5. The composition of claim 1 wherein the carboxylic acid componentcomprises a mixture of isostearic acid and octadecylsuccinic acid or-anhydride.
 6. The composition of claim 1 wherein each of the twohydrocarbyl groups contains at least about 8 carbon atoms.
 7. Thecomposition of claim 1 wherein the dispersant of (b) is a carboxylicdispersant, a succinimide dispersant, an amine dispersant, or a Mannichdispersant.
 8. The composition of claim 1 further comprising an oil oflubricating viscosity.
 9. The composition of claim 8 wherein the amountof component (a) is about 0.2 to about 5 percent by weight of thecomposition and component (b) is about 1 to about 4 percent by weight ofthe composition.
 10. The composition of claim 8 further comprising aviscosity modifier, a supplemental friction modifier, a detergent, anoxidation inhibitor, or a phosphorus compound.
 11. A method forlubricating a transmission, tractor, engine, gearbox, or bearing,comprising supplying thereto the composition of claim
 1. 12. A methodfor lubricating a transmission, tractor, engine, gearbox, or bearing,comprising supplying thereto a friction modifier derived from thereaction of a carboxylic acid or a reactive equivalent thereof with anaminoalcohol, wherein the friction modifier contains at least twohydrocarbyl groups each containing at least about 6 carbon atoms.